Composition and method for dielectric cmp

Abstract

A chemical mechanical polishing composition for polishing a substrate having a silicon oxygen material comprises, consists of, or consists essentially of a liquid carrier, cubiform ceria abrasive particles dispersed in the liquid carrier, and a cationic polymer having a charge density of greater than about 6 meq/g.

1 . A chemical mechanical polishing composition comprising:
 a liquid carrier;   cubiform ceria abrasive particles dispersed in the liquid carrier; and   a cationic polymer having a charge density of greater than about 6 milliequivalents per gram (meq/g).   
     
     
         2 . The composition of  claim 1 , wherein the cubiform ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide. 
     
     
         3 . The composition of  claim 1 , wherein the cubiform ceria abrasive particles have a molar ratio of lanthanum to lanthanum plus cerium in a range from about 1 to about 15 percent. 
     
     
         4 . The composition of  claim 1 , wherein the cubiform ceria abrasive particles have a BET surface area in a range from about 3 m 2 /g to about 14 m 2 /g. 
     
     
         5 . The composition of  claim 1 , wherein the cubiform ceria abrasive particles have an average particle size in a range from about 50 nm to about 500 nm. 
     
     
         6 . The composition of  claim 1 , comprising from about 0.001 to about 1 weight percent of the cubiform ceria abrasive particles at point of use. 
     
     
         7 . The composition of  claim 1 , wherein the cationic polymer has a charge density of greater than about 9 meq/g. 
     
     
         8 . The composition of  claim 1 , wherein the cationic polymer comprises at least one of poly(vinylimidazole), poly(vinylimidazolium), poly(vinylmethyl imidazolium), epichlorhydrin-dimethylamine, polydiallyl dimethyl ammonium, poly(vinylmethyl imidazolium) methyl sulfate, polyethylenimine, polylysine, polyhistidine, polyarginine. 
     
     
         9 . The composition  claim 1 , wherein the cationic polymer is poly(vinylimidazolium), polylysine, or a mixture thereof. 
     
     
         10 . The composition of  claim 1 , comprising from about 0.1 ppm by weight to about 20 ppm by weight of the cationic polymer at point of use. 
     
     
         11 . The composition of  claim 1 , comprising from about 1 ppm by weight to about 10 ppm by weight of the cationic polymer at point of use. 
     
     
         12 . The composition of  claim 1 , further comprising a carboxylic acid silicon oxide polishing rate enhancer. 
     
     
         13 . The composition of  claim 12 , wherein the carboxylic acid is picolinic acid, acetic acid, 4-hydroxybenzoic acid, or a mixture thereof. 
     
     
         14 . The composition of  claim 1 , having a pH in a range from about 3 to about 6 at point of use. 
     
     
         15 . The composition of  claim 1 , comprising:
 from about 0.001 to about 1 weight percent of the cubiform ceria abrasive particles at point of use; and   from about 0.1 ppm by weight to about 20 ppm by weight poly(vinylimidazolium), polylysine, or a mixture thereof at point of use.   
     
     
         16 . The composition of  claim 15 , having a pH in a range from about 3 to 6 at point of use and further comprising picolinic acid, acetic acid, or a mixture thereof. 
     
     
         17 . The composition of  claim 1 , comprising from about 0.001 to about 1 weight percent of the cubiform ceria abrasive particles at point of use, wherein:
 the cubiform ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size in a range from about 50 to about 500 nm; and   the cationic polymer includes poly(vinylimidazolium), polylysine, or a mixture thereof.   
     
     
         18 . The composition of  claim 17 , having a pH in a range from about 3 to 6 at point of use and further comprising picolinic acid, acetic acid, or a mixture thereof. 
     
     
         19 . A method of chemical mechanical polishing a substrate including a silicon oxide dielectric material, the method comprising:
 (a) providing a polishing composition including a liquid carrier, cubiform ceria abrasive particles dispersed in the liquid carrier, and a cationic polymer having a charge density of greater than about 6 meq/g;   (b) contacting the substrate with said provided polishing composition;   (c) moving said polishing composition relative to the substrate; and   (d) abrading the substrate to remove a portion of the silicon oxide dielectric material from the substrate and thereby polish the substrate.   
     
     
         20 . The method of  claim 19 , wherein a removal rate of the silicon oxide dielectric material is greater than about 6,000 Å/min. 
     
     
         21 . The method of  claim 19 , wherein the cationic polymer is polylysine or poly(vinylimidazolium). 
     
     
         22 . The method of  claim 19 , wherein:
 the polishing composition comprises from about 0.001 to about 1 weight percent of the cubiform ceria abrasive particles at point of use, and   the cubiform ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size in a range from about 50 to about 500 nm.   
     
     
         23 . The method of  claim 19 , wherein the polishing composition further comprises picolinic acid, acetic acid, or a mixture thereof.